Apple held its keynote speech just now, kicking off its developer conference. The company announced minor refreshes for its laptop line, introduced a stunning new laptop with a Retina display, and gave a sneak peek of iOS 6, which will launch in the Fall.

In Windows 7, an app declares in its manifest whether its "DPI-aware" or not. If so, then W7 doesn't do anything to the app, since the app handles high DPI on its own (and when it's done right, it's very good).

But if an app doesn't declare itself to be DPI aware, then W7 uses XP DPI scaling for DPI between 100% and 125% (where 100% is 96 DPI), then above 125% W7 just does a bitmap scaling, which looks horrible (though its more "accurate" than what XP would do). This is the default behavior, but the user can change that behavior in the DPI Control Panel (that is, the user can change the threshold for XP DPI scaling, and I think a user can choose to always use XP behavior for non-DPI aware apps).

Note: I typed the above from memory; I don't vouch for it to be 100% accurate.